California fires ‘exceeding what our models will even...

1of3Houses remain standing and with little damage in view of others that were destroyed in a wildfire several days earlier, Tuesday, Sept. 15, 2015, in Middletown, Calif. The fire that sped through Middletown and other parts of rural Lake County, less than 100 miles north of San Francisco, has continued to burn since Saturday despite a massive firefighting effort. (AP Photo/Elaine Thompson)Photo: Elaine Thompson, STF / Associated Press

2of3Richard and Kathie Reeves stand in the remains of the home of friends in Middletown, Calif. A wildfire in Lake County torched over 60 square miles.Photo: Elaine Thompson /Associated Press

3of3MIDDLETOWN, CA - SEPTEMBER 15: The ruins of a home that burned in the Valley Fire are seen on September 15, 2015 in Middletown, California. The 104-square-mile fire is only 15 percent contained and has destroyed 585 homes so far and hundreds of other structures. (Photo by David McNew/Getty Images)Photo: David McNew, Stringer / Getty Images

SACRAMENTO, Calif. — Wildfires that have raged in California this summer haven’t just overwhelmed firefighters — they’ve also stumped computer models designed to predict the intensity of flames and where they’ll burn.

“These fires are actually exceeding what our models will even predict,” said Ken Pimlott, director of the California Department of Forestry and Fire Protection.

While rapidly spreading wildfires exacerbated by four years of drought may have made wildfires harder to forecast, others suggest modeling methods haven’t kept up to speed with technology.

Modeling has been a primary tool for nearly 40 years for fire managers to plot where a fire will run and help plan where they should deploy firefighters, dig containment lines, fly water- and retardant-dropping aircraft and order evacuations.

But it’s not an exact science, and it’s often only as good as the expert doing the analysis and a little trial and error.

Modeling experts who work for fire agencies plug variables such as vegetation type, humidity, temperature and terrain into a computer program to create virtual fires and see how they progress. Forecasts are usually created twice a day and shared with managers on the ground to make tactical decisions that day and to plan for days ahead.

“It’s imperfect,” said Rick Stratton, a fire analyst for the U.S. Forest Service. “More often than not, the science, I don’t want to say it’s right, but it helps make a risk-informed decision.”